A. Field of the Invention
This invention relates to novel carpets, and particularly to novel carpets having a pile wherein the individual tufts of the pile are made from synthetic continuous filament yarns. The invention also relates to a novel process for producing such carpets.
B. Description of the Prior Art
The pile of carpets is made from yarns that may either be spun from staple fibers in the traditional way or may be of the continuous filament type. Continuous filament yarns, for example of nylon, are normally textured in some way and the filaments are either twisted or tangled together so as to give them coherence. Continuous filament yarns are usually cheaper to produce than staple yarns but carpets made from them may sometimes present a somewhat less than ideal appearance when the pile is cut, for example, to form a velour surface rather than a loop pile surface. In particular, not only is there a tendency towards loss of tuft identity but also the carpet can present a streaky appearance which is due to slight differences in texturing at different places along the length of the yarn. Pile yarns made from staple fibers are normally better in these respects but their production involves more process steps and often, depending on pile height, their cost is substantially higher. There is therefore a need for a carpet, particularly a velour carpet, having a pile made from continuous filament yarn and having an improved tuft identity and freedom from streaks.
It has been proposed, in British Pat. No. 1,217,226, to produce multifilament yarns by combining two thermoplastic yarns that have been differently heated and then crimped so as to produce differing latent crimp development characteristics in the two yarns, and then treating the combined yarn to develop the differing latent crimp characteristics. The yarns can be used in carpet pile and give reduced "rowiness". However, as explained in the British Patent, "rowiness" is caused by pile tufts standing upright in rows and is a mechanical phenomenon. It is not to be confused with "streaking" resulting from texturing variations, which is the problem to which the present invention is addressed, as explained above. Further, a "rowy" appearance very often shows as rows extending transversely across the machine direction whereas streaks extend in the machine direction; this is a consequence of the different reasons for occurrence of the two phenomena.
It has also been proposed, in U.S. Pat. Nos. 3,061,998, and 3,175,351, to produce a bulked continuous singles yarn in which some of the filaments are crimped to provide bulk and others are in relatively straight form to provide dimensional stability. Other patents proposing combined yarns comprising crimped and non-crimped filaments are British Pat. Nos. 1,000,366, 1,454,521 and 1,459,098. However, these U.S. and British patents do not propose the use of such yarns in carpets and in particular do not contain any teaching concerning the problem of streaking in cut pile carpets.